Ceramic cements are mixtures of water and reactive metal oxides that harden and fasten upon setting. Cements have a variety of familiar uses, such as the adhesive component to concrete (essentially an agglomeration of rocks held together by cement), the bonding layer that holds bricks together to form walls, as structural building materials such as patio or garage slabs, as the matrix component of ceramic composite materials, and the like.
Ceramic composite materials use cements as a matrix to support a distribution of other materials therein. These materials may be fibers, spheres, rods, needles, irregularly shaped objects, or the like, as well as combinations thereof. While concrete is the most obvious example of a ceramic composite material, such composites may be compositionally tailored to yield desired combinations of physical properties.
Furnace linings, for example, may be made of ceramic composites. One requirement of furnace lining materials is that they be refractory. Another desired furnace lining property is a resistance to oxidation, while others include resistance to chemical attack, strength, and toughness. Silicon carbide is an inexpensive, chemically stable, and tough refractory material that is well suited for cementitious composite applications. However, SiC is prone to oxidation, yielding silica and carbon dioxide. Anti-oxidation additives, such as boron containing materials like BN, Si metal, Al metal, and/or carbonaceous materials are commonly included in SiC-cement composites to retard oxidation of SiC. However, these anti-oxidants typically detract from the other desired parameters, such as refractoriness, toughness, strength, and the like, as well as increase the cost of the material and/or introduce thermal expansion mismatches into the matrix that give rise to creep and degradation over time and with thermal cycling. Thus, there is a need for a SiC-cement composite that is oxidation resistant without sacrificing other desired parameters. The present novel technology addresses this need.